Study Guide Bava Kamma 52 This week's learning is sponsored by Michelle Feiglin in loving memory of her father, Natan ben Devorah v'Shlomo Elimelech on his 8th yahrzeit and for the refuah shleima of her grandson, Neriya Yosef Hoshea ben Avital. "My father was liberated from Buchenwald and rebuilt his life in Melbourne, Australia. He inspired my love of learning Torah and every lunchtime in the middle of his working day could be found in front of his Gemara. He had great success in business, but he always said that his biggest success was his family."  This week's learning is sponsored for the refuah shleima of Shelly bat Sara Nina. Land can be acquired in three ways, by money, a document or chazaka (using the land in a way that shows ownership). When can a pit or a house, which are both considered like land) be acquired by passing over an item? Does it depend on what item? How can this be effective? A flock of animals can also be acquired by passing a particular item - what item and how does the kinyan work? If two people own a cistern and the first person covered it and the second one passed by and found it uncovered but didn't cover it, the second owner is responsible. At what point would the first owner revert to being responsible for it together with the second owner? Would it be only if the first person sees it or hears it is uncovered or do they also get extra time to hire people to close it once the first owner hears about it? The Mishna explains that if the owner covers it and the animal falls in, the owner is not responsible. If it was covered, how can this be? Rabbi Yitzchak says that the cover must have rotted. Two different versions of a question are brought and the Gemara attempts to answer the question from our Mishna but is unsuccessful. The first version of the question is about one who covered a cistern with a cover that could withstand oxen but not camels. If a camel weakened it and then the ox fell in, is the owner held responsible? The second version is that the question was about a cover that could withstand both oxen but not camels, and camels commonly pass by. However, the cover was not weakened by camels but rotted. Is the law that since the owner was negligent as the cover could not withstand camels, the owner is considered negligent regarding rotting, even though it is highly unlikely that the cover would rot? Or is the law that since rotting was unexpected, the owner is exempt? The second version of the question is ultimately answered from a braita.